172 INTERNAL COMBUSTION ENGINE [CHAP.V

between them. The mass of piston C with its attached recipro-
parts is 8 tons, that of A is 4 tons. The stroke of each piston
is 43 in., and length of each connecting rod is 108 in. Find the magni-
tude direction of the unbalanced horizontal inertia force on the
engine at each dead-point, when the speed is 100 revs, per min.

It is often assumed in the calculation of inertia forces that the con-
necting rod may be treated as though half its mass were concentrated
at end. Discuss this assumption and explain its practical con-

sequences in regard to the problem of balancing.

(Mech. Sc. Tripos, 1913.)
17. Hie two
indicator dia-
grams * here-
w i t h were
taken from a
The

temperature at

the point A

measured

directly and

found to be

100° 0. The

corresponding

and

volume be
found from the
diagram. CM-
the tem-
perature at the
point B. What
further data
Are required to
you to

calculate the temperature at a point C on the expansion line ?
The pressure of the atmosphere is 14-7 lb. per sq. inch, and the clear-

is -y of displacement volume.

Use cylinder of the engine is 5-5 in. diameter and the stroke 10 in.
The B.H.P. of the engine was varied, and the speed was maintained
iby^a hit-and-miss governor) approximately constant at 370 r.p.m.
during the trials. Determine from the diagrams and the following

the fnetiona! HLP. of the engine for each loading:__

BJBLP......5-51 3-78 1*6 0

per min, . . 150 120 75 44

(B. of E., 1913.)
* two are not really consistent, but the puestion is

006